Yes, memset_s().
Which makes me think there should be a free_s().
The compiler can, and will, make copies of data behind the scenes. And not erase said copies.
What we really need is a keyword / modifier that says that when X passes out of scope no state related to X may be leaked. Ideally, that can be applied to a function / block as well as a variable.
(Or rather, not necessarily no state. Read "as little state as possible", preferably with modifiers that panic unless the compiler can ensure specific things.)
On the other hand, something as simple as a keyword marking a variable as "as secure as possible given hardware constraints (read: should wipe any temporary copies and the variable itself after it goes out of scope, should attempt to prevent it from being written to non-volatile storage, that sort of thing)" (sort of like how inline works), with compilers required to bail if the constraint cannot be done to the level specified, would be a massive step in the right direction.